/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.] */
#include <openssl/rsa.h>
#include <string.h>
#include <openssl/bn.h>
#include <openssl/err.h>
#include <openssl/mem.h>
#include <openssl/thread.h>
#include "internal.h"
#include "../internal.h"
#define OPENSSL_RSA_MAX_MODULUS_BITS 16384
#define OPENSSL_RSA_SMALL_MODULUS_BITS 3072
#define OPENSSL_RSA_MAX_PUBEXP_BITS \
64 /* exponent limit enforced for "large" modulus only */
static int finish(RSA *rsa) {
BN_MONT_CTX_free(rsa->_method_mod_n);
BN_MONT_CTX_free(rsa->_method_mod_p);
BN_MONT_CTX_free(rsa->_method_mod_q);
return 1;
}
static size_t size(const RSA *rsa) {
return BN_num_bytes(rsa->n);
}
static int encrypt(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out,
const uint8_t *in, size_t in_len, int padding) {
const unsigned rsa_size = RSA_size(rsa);
BIGNUM *f, *result;
uint8_t *buf = NULL;
BN_CTX *ctx = NULL;
int i, ret = 0;
if (rsa_size > OPENSSL_RSA_MAX_MODULUS_BITS) {
OPENSSL_PUT_ERROR(RSA, encrypt, RSA_R_MODULUS_TOO_LARGE);
return 0;
}
if (max_out < rsa_size) {
OPENSSL_PUT_ERROR(RSA, encrypt, RSA_R_OUTPUT_BUFFER_TOO_SMALL);
return 0;
}
if (BN_ucmp(rsa->n, rsa->e) <= 0) {
OPENSSL_PUT_ERROR(RSA, encrypt, RSA_R_BAD_E_VALUE);
return 0;
}
/* for large moduli, enforce exponent limit */
if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS &&
BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) {
OPENSSL_PUT_ERROR(RSA, encrypt, RSA_R_BAD_E_VALUE);
return 0;
}
ctx = BN_CTX_new();
if (ctx == NULL) {
goto err;
}
BN_CTX_start(ctx);
f = BN_CTX_get(ctx);
result = BN_CTX_get(ctx);
buf = OPENSSL_malloc(rsa_size);
if (!f || !result || !buf) {
OPENSSL_PUT_ERROR(RSA, encrypt, ERR_R_MALLOC_FAILURE);
goto err;
}
switch (padding) {
case RSA_PKCS1_PADDING:
i = RSA_padding_add_PKCS1_type_2(buf, rsa_size, in, in_len);
break;
case RSA_PKCS1_OAEP_PADDING:
/* Use the default parameters: SHA-1 for both hashes and no label. */
i = RSA_padding_add_PKCS1_OAEP_mgf1(buf, rsa_size, in, in_len,
NULL, 0, NULL, NULL);
break;
case RSA_NO_PADDING:
i = RSA_padding_add_none(buf, rsa_size, in, in_len);
break;
default:
OPENSSL_PUT_ERROR(RSA, encrypt, RSA_R_UNKNOWN_PADDING_TYPE);
goto err;
}
if (i <= 0) {
goto err;
}
if (BN_bin2bn(buf, rsa_size, f) == NULL) {
goto err;
}
if (BN_ucmp(f, rsa->n) >= 0) {
/* usually the padding functions would catch this */
OPENSSL_PUT_ERROR(RSA, encrypt, RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
goto err;
}
if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) {
if (BN_MONT_CTX_set_locked(&rsa->_method_mod_n, &rsa->lock, rsa->n, ctx) ==
NULL) {
goto err;
}
}
if (!rsa->meth->bn_mod_exp(result, f, rsa->e, rsa->n, ctx,
rsa->_method_mod_n)) {
goto err;
}
/* put in leading 0 bytes if the number is less than the length of the
* modulus */
if (!BN_bn2bin_padded(out, rsa_size, result)) {
OPENSSL_PUT_ERROR(RSA, encrypt, ERR_R_INTERNAL_ERROR);
goto err;
}
*out_len = rsa_size;
ret = 1;
err:
if (ctx != NULL) {
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (buf != NULL) {
OPENSSL_cleanse(buf, rsa_size);
OPENSSL_free(buf);
}
return ret;
}
/* MAX_BLINDINGS_PER_RSA defines the maximum number of cached BN_BLINDINGs per
* RSA*. Then this limit is exceeded, BN_BLINDING objects will be created and
* destroyed as needed. */
#define MAX_BLINDINGS_PER_RSA 1024
/* rsa_blinding_get returns a BN_BLINDING to use with |rsa|. It does this by
* allocating one of the cached BN_BLINDING objects in |rsa->blindings|. If
* none are free, the cache will be extended by a extra element and the new
* BN_BLINDING is returned.
*
* On success, the index of the assigned BN_BLINDING is written to
* |*index_used| and must be passed to |rsa_blinding_release| when finished. */
static BN_BLINDING *rsa_blinding_get(RSA *rsa, unsigned *index_used,
BN_CTX *ctx) {
BN_BLINDING *ret = NULL;
BN_BLINDING **new_blindings;
uint8_t *new_blindings_inuse;
char overflow = 0;
CRYPTO_MUTEX_lock_write(&rsa->lock);
unsigned i;
for (i = 0; i < rsa->num_blindings; i++) {
if (rsa->blindings_inuse[i] == 0) {
rsa->blindings_inuse[i] = 1;
ret = rsa->blindings[i];
*index_used = i;
break;
}
}
if (ret != NULL) {
CRYPTO_MUTEX_unlock(&rsa->lock);
return ret;
}
overflow = rsa->num_blindings >= MAX_BLINDINGS_PER_RSA;
/* We didn't find a free BN_BLINDING to use so increase the length of
* the arrays by one and use the newly created element. */
CRYPTO_MUTEX_unlock(&rsa->lock);
ret = rsa_setup_blinding(rsa, ctx);
if (ret == NULL) {
return NULL;
}
if (overflow) {
/* We cannot add any more cached BN_BLINDINGs so we use |ret|
* and mark it for destruction in |rsa_blinding_release|. */
*index_used = MAX_BLINDINGS_PER_RSA;
return ret;
}
CRYPTO_MUTEX_lock_write(&rsa->lock);
new_blindings =
OPENSSL_malloc(sizeof(BN_BLINDING *) * (rsa->num_blindings + 1));
if (new_blindings == NULL) {
goto err1;
}
memcpy(new_blindings, rsa->blindings,
sizeof(BN_BLINDING *) * rsa->num_blindings);
new_blindings[rsa->num_blindings] = ret;
new_blindings_inuse = OPENSSL_malloc(rsa->num_blindings + 1);
if (new_blindings_inuse == NULL) {
goto err2;
}
memcpy(new_blindings_inuse, rsa->blindings_inuse, rsa->num_blindings);
new_blindings_inuse[rsa->num_blindings] = 1;
*index_used = rsa->num_blindings;
OPENSSL_free(rsa->blindings);
rsa->blindings = new_blindings;
OPENSSL_free(rsa->blindings_inuse);
rsa->blindings_inuse = new_blindings_inuse;
rsa->num_blindings++;
CRYPTO_MUTEX_unlock(&rsa->lock);
return ret;
err2:
OPENSSL_free(new_blindings);
err1:
CRYPTO_MUTEX_unlock(&rsa->lock);
BN_BLINDING_free(ret);
return NULL;
}
/* rsa_blinding_release marks the cached BN_BLINDING at the given index as free
* for other threads to use. */
static void rsa_blinding_release(RSA *rsa, BN_BLINDING *blinding,
unsigned blinding_index) {
if (blinding_index == MAX_BLINDINGS_PER_RSA) {
/* This blinding wasn't cached. */
BN_BLINDING_free(blinding);
return;
}
CRYPTO_MUTEX_lock_write(&rsa->lock);
rsa->blindings_inuse[blinding_index] = 0;
CRYPTO_MUTEX_unlock(&rsa->lock);
}
/* signing */
static int sign_raw(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out,
const uint8_t *in, size_t in_len, int padding) {
const unsigned rsa_size = RSA_size(rsa);
uint8_t *buf = NULL;
int i, ret = 0;
if (max_out < rsa_size) {
OPENSSL_PUT_ERROR(RSA, sign_raw, RSA_R_OUTPUT_BUFFER_TOO_SMALL);
return 0;
}
buf = OPENSSL_malloc(rsa_size);
if (buf == NULL) {
OPENSSL_PUT_ERROR(RSA, sign_raw, ERR_R_MALLOC_FAILURE);
goto err;
}
switch (padding) {
case RSA_PKCS1_PADDING:
i = RSA_padding_add_PKCS1_type_1(buf, rsa_size, in, in_len);
break;
case RSA_NO_PADDING:
i = RSA_padding_add_none(buf, rsa_size, in, in_len);
break;
default:
OPENSSL_PUT_ERROR(RSA, sign_raw, RSA_R_UNKNOWN_PADDING_TYPE);
goto err;
}
if (i <= 0) {
goto err;
}
if (!RSA_private_transform(rsa, out, buf, rsa_size)) {
goto err;
}
*out_len = rsa_size;
ret = 1;
err:
if (buf != NULL) {
OPENSSL_cleanse(buf, rsa_size);
OPENSSL_free(buf);
}
return ret;
}
static int decrypt(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out,
const uint8_t *in, size_t in_len, int padding) {
const unsigned rsa_size = RSA_size(rsa);
int r = -1;
uint8_t *buf = NULL;
int ret = 0;
if (max_out < rsa_size) {
OPENSSL_PUT_ERROR(RSA, decrypt, RSA_R_OUTPUT_BUFFER_TOO_SMALL);
return 0;
}
buf = OPENSSL_malloc(rsa_size);
if (buf == NULL) {
OPENSSL_PUT_ERROR(RSA, decrypt, ERR_R_MALLOC_FAILURE);
goto err;
}
if (in_len != rsa_size) {
OPENSSL_PUT_ERROR(RSA, decrypt, RSA_R_DATA_LEN_NOT_EQUAL_TO_MOD_LEN);
goto err;
}
if (!RSA_private_transform(rsa, buf, in, rsa_size)) {
goto err;
}
switch (padding) {
case RSA_PKCS1_PADDING:
r = RSA_padding_check_PKCS1_type_2(out, rsa_size, buf, rsa_size);
break;
case RSA_PKCS1_OAEP_PADDING:
/* Use the default parameters: SHA-1 for both hashes and no label. */
r = RSA_padding_check_PKCS1_OAEP_mgf1(out, rsa_size, buf, rsa_size,
NULL, 0, NULL, NULL);
break;
case RSA_NO_PADDING:
r = RSA_padding_check_none(out, rsa_size, buf, rsa_size);
break;
default:
OPENSSL_PUT_ERROR(RSA, decrypt, RSA_R_UNKNOWN_PADDING_TYPE);
goto err;
}
if (r < 0) {
OPENSSL_PUT_ERROR(RSA, decrypt, RSA_R_PADDING_CHECK_FAILED);
} else {
*out_len = r;
ret = 1;
}
err:
if (buf != NULL) {
OPENSSL_cleanse(buf, rsa_size);
OPENSSL_free(buf);
}
return ret;
}
static int verify_raw(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out,
const uint8_t *in, size_t in_len, int padding) {
const unsigned rsa_size = RSA_size(rsa);
BIGNUM *f, *result;
int ret = 0;
int r = -1;
uint8_t *buf = NULL;
BN_CTX *ctx = NULL;
if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) {
OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_MODULUS_TOO_LARGE);
return 0;
}
if (BN_ucmp(rsa->n, rsa->e) <= 0) {
OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_BAD_E_VALUE);
return 0;
}
if (max_out < rsa_size) {
OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_OUTPUT_BUFFER_TOO_SMALL);
return 0;
}
/* for large moduli, enforce exponent limit */
if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS &&
BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) {
OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_BAD_E_VALUE);
return 0;
}
ctx = BN_CTX_new();
if (ctx == NULL) {
goto err;
}
BN_CTX_start(ctx);
f = BN_CTX_get(ctx);
result = BN_CTX_get(ctx);
buf = OPENSSL_malloc(rsa_size);
if (!f || !result || !buf) {
OPENSSL_PUT_ERROR(RSA, verify_raw, ERR_R_MALLOC_FAILURE);
goto err;
}
if (in_len != rsa_size) {
OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_DATA_LEN_NOT_EQUAL_TO_MOD_LEN);
goto err;
}
if (BN_bin2bn(in, in_len, f) == NULL) {
goto err;
}
if (BN_ucmp(f, rsa->n) >= 0) {
OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
goto err;
}
if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) {
if (BN_MONT_CTX_set_locked(&rsa->_method_mod_n, &rsa->lock, rsa->n, ctx) ==
NULL) {
goto err;
}
}
if (!rsa->meth->bn_mod_exp(result, f, rsa->e, rsa->n, ctx,
rsa->_method_mod_n)) {
goto err;
}
if (!BN_bn2bin_padded(buf, rsa_size, result)) {
OPENSSL_PUT_ERROR(RSA, verify_raw, ERR_R_INTERNAL_ERROR);
goto err;
}
switch (padding) {
case RSA_PKCS1_PADDING:
r = RSA_padding_check_PKCS1_type_1(out, rsa_size, buf, rsa_size);
break;
case RSA_NO_PADDING:
r = RSA_padding_check_none(out, rsa_size, buf, rsa_size);
break;
default:
OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_UNKNOWN_PADDING_TYPE);
goto err;
}
if (r < 0) {
OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_PADDING_CHECK_FAILED);
} else {
*out_len = r;
ret = 1;
}
err:
if (ctx != NULL) {
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (buf != NULL) {
OPENSSL_cleanse(buf, rsa_size);
OPENSSL_free(buf);
}
return ret;
}
static int private_transform(RSA *rsa, uint8_t *out, const uint8_t *in,
size_t len) {
BIGNUM *f, *result;
BN_CTX *ctx = NULL;
unsigned blinding_index = 0;
BN_BLINDING *blinding = NULL;
int ret = 0;
ctx = BN_CTX_new();
if (ctx == NULL) {
goto err;
}
BN_CTX_start(ctx);
f = BN_CTX_get(ctx);
result = BN_CTX_get(ctx);
if (f == NULL || result == NULL) {
OPENSSL_PUT_ERROR(RSA, private_transform, ERR_R_MALLOC_FAILURE);
goto err;
}
if (BN_bin2bn(in, len, f) == NULL) {
goto err;
}
if (BN_ucmp(f, rsa->n) >= 0) {
/* Usually the padding functions would catch this. */
OPENSSL_PUT_ERROR(RSA, private_transform, RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
goto err;
}
if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) {
blinding = rsa_blinding_get(rsa, &blinding_index, ctx);
if (blinding == NULL) {
OPENSSL_PUT_ERROR(RSA, private_transform, ERR_R_INTERNAL_ERROR);
goto err;
}
if (!BN_BLINDING_convert_ex(f, NULL, blinding, ctx)) {
goto err;
}
}
if ((rsa->flags & RSA_FLAG_EXT_PKEY) ||
((rsa->p != NULL) && (rsa->q != NULL) && (rsa->dmp1 != NULL) &&
(rsa->dmq1 != NULL) && (rsa->iqmp != NULL))) {
if (!rsa->meth->mod_exp(result, f, rsa, ctx)) {
goto err;
}
} else {
BIGNUM local_d;
BIGNUM *d = NULL;
BN_init(&local_d);
d = &local_d;
BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) {
if (BN_MONT_CTX_set_locked(&rsa->_method_mod_n, &rsa->lock, rsa->n,
ctx) == NULL) {
goto err;
}
}
if (!rsa->meth->bn_mod_exp(result, f, d, rsa->n, ctx, rsa->_method_mod_n)) {
goto err;
}
}
if (blinding) {
if (!BN_BLINDING_invert_ex(result, NULL, blinding, ctx)) {
goto err;
}
}
if (!BN_bn2bin_padded(out, len, result)) {
OPENSSL_PUT_ERROR(RSA, private_transform, ERR_R_INTERNAL_ERROR);
goto err;
}
ret = 1;
err:
if (ctx != NULL) {
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (blinding != NULL) {
rsa_blinding_release(rsa, blinding, blinding_index);
}
return ret;
}
static int mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx) {
BIGNUM *r1, *m1, *vrfy;
BIGNUM local_dmp1, local_dmq1, local_c, local_r1;
BIGNUM *dmp1, *dmq1, *c, *pr1;
int ret = 0;
BN_CTX_start(ctx);
r1 = BN_CTX_get(ctx);
m1 = BN_CTX_get(ctx);
vrfy = BN_CTX_get(ctx);
{
BIGNUM local_p, local_q;
BIGNUM *p = NULL, *q = NULL;
/* Make sure BN_mod_inverse in Montgomery intialization uses the
* BN_FLG_CONSTTIME flag (unless RSA_FLAG_NO_CONSTTIME is set) */
BN_init(&local_p);
p = &local_p;
BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
BN_init(&local_q);
q = &local_q;
BN_with_flags(q, rsa->q, BN_FLG_CONSTTIME);
if (rsa->flags & RSA_FLAG_CACHE_PRIVATE) {
if (BN_MONT_CTX_set_locked(&rsa->_method_mod_p, &rsa->lock, p, ctx) ==
NULL) {
goto err;
}
if (BN_MONT_CTX_set_locked(&rsa->_method_mod_q, &rsa->lock, q, ctx) ==
NULL) {
goto err;
}
}
}
if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) {
if (BN_MONT_CTX_set_locked(&rsa->_method_mod_n, &rsa->lock, rsa->n, ctx) ==
NULL) {
goto err;
}
}
/* compute I mod q */
c = &local_c;
BN_with_flags(c, I, BN_FLG_CONSTTIME);
if (!BN_mod(r1, c, rsa->q, ctx)) {
goto err;
}
/* compute r1^dmq1 mod q */
dmq1 = &local_dmq1;
BN_with_flags(dmq1, rsa->dmq1, BN_FLG_CONSTTIME);
if (!rsa->meth->bn_mod_exp(m1, r1, dmq1, rsa->q, ctx, rsa->_method_mod_q)) {
goto err;
}
/* compute I mod p */
c = &local_c;
BN_with_flags(c, I, BN_FLG_CONSTTIME);
if (!BN_mod(r1, c, rsa->p, ctx)) {
goto err;
}
/* compute r1^dmp1 mod p */
dmp1 = &local_dmp1;
BN_with_flags(dmp1, rsa->dmp1, BN_FLG_CONSTTIME);
if (!rsa->meth->bn_mod_exp(r0, r1, dmp1, rsa->p, ctx, rsa->_method_mod_p)) {
goto err;
}
if (!BN_sub(r0, r0, m1)) {
goto err;
}
/* This will help stop the size of r0 increasing, which does
* affect the multiply if it optimised for a power of 2 size */
if (BN_is_negative(r0)) {
if (!BN_add(r0, r0, rsa->p)) {
goto err;
}
}
if (!BN_mul(r1, r0, rsa->iqmp, ctx)) {
goto err;
}
/* Turn BN_FLG_CONSTTIME flag on before division operation */
pr1 = &local_r1;
BN_with_flags(pr1, r1, BN_FLG_CONSTTIME);
if (!BN_mod(r0, pr1, rsa->p, ctx)) {
goto err;
}
/* If p < q it is occasionally possible for the correction of
* adding 'p' if r0 is negative above to leave the result still
* negative. This can break the private key operations: the following
* second correction should *always* correct this rare occurrence.
* This will *never* happen with OpenSSL generated keys because
* they ensure p > q [steve] */
if (BN_is_negative(r0)) {
if (!BN_add(r0, r0, rsa->p)) {
goto err;
}
}
if (!BN_mul(r1, r0, rsa->q, ctx)) {
goto err;
}
if (!BN_add(r0, r1, m1)) {
goto err;
}
if (rsa->e && rsa->n) {
if (!rsa->meth->bn_mod_exp(vrfy, r0, rsa->e, rsa->n, ctx,
rsa->_method_mod_n)) {
goto err;
}
/* If 'I' was greater than (or equal to) rsa->n, the operation
* will be equivalent to using 'I mod n'. However, the result of
* the verify will *always* be less than 'n' so we don't check
* for absolute equality, just congruency. */
if (!BN_sub(vrfy, vrfy, I)) {
goto err;
}
if (!BN_mod(vrfy, vrfy, rsa->n, ctx)) {
goto err;
}
if (BN_is_negative(vrfy)) {
if (!BN_add(vrfy, vrfy, rsa->n)) {
goto err;
}
}
if (!BN_is_zero(vrfy)) {
/* 'I' and 'vrfy' aren't congruent mod n. Don't leak
* miscalculated CRT output, just do a raw (slower)
* mod_exp and return that instead. */
BIGNUM local_d;
BIGNUM *d = NULL;
d = &local_d;
BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
if (!rsa->meth->bn_mod_exp(r0, I, d, rsa->n, ctx, rsa->_method_mod_n)) {
goto err;
}
}
}
ret = 1;
err:
BN_CTX_end(ctx);
return ret;
}
static int keygen(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb) {
BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *r3 = NULL, *tmp;
BIGNUM local_r0, local_d, local_p;
BIGNUM *pr0, *d, *p;
int bitsp, bitsq, ok = -1, n = 0;
BN_CTX *ctx = NULL;
ctx = BN_CTX_new();
if (ctx == NULL) {
goto err;
}
BN_CTX_start(ctx);
r0 = BN_CTX_get(ctx);
r1 = BN_CTX_get(ctx);
r2 = BN_CTX_get(ctx);
r3 = BN_CTX_get(ctx);
if (r3 == NULL) {
goto err;
}
bitsp = (bits + 1) / 2;
bitsq = bits - bitsp;
/* We need the RSA components non-NULL */
if (!rsa->n && ((rsa->n = BN_new()) == NULL)) {
goto err;
}
if (!rsa->d && ((rsa->d = BN_new()) == NULL)) {
goto err;
}
if (!rsa->e && ((rsa->e = BN_new()) == NULL)) {
goto err;
}
if (!rsa->p && ((rsa->p = BN_new()) == NULL)) {
goto err;
}
if (!rsa->q && ((rsa->q = BN_new()) == NULL)) {
goto err;
}
if (!rsa->dmp1 && ((rsa->dmp1 = BN_new()) == NULL)) {
goto err;
}
if (!rsa->dmq1 && ((rsa->dmq1 = BN_new()) == NULL)) {
goto err;
}
if (!rsa->iqmp && ((rsa->iqmp = BN_new()) == NULL)) {
goto err;
}
BN_copy(rsa->e, e_value);
/* generate p and q */
for (;;) {
if (!BN_generate_prime_ex(rsa->p, bitsp, 0, NULL, NULL, cb) ||
!BN_sub(r2, rsa->p, BN_value_one()) ||
!BN_gcd(r1, r2, rsa->e, ctx)) {
goto err;
}
if (BN_is_one(r1)) {
break;
}
if (!BN_GENCB_call(cb, 2, n++)) {
goto err;
}
}
if (!BN_GENCB_call(cb, 3, 0)) {
goto err;
}
for (;;) {
/* When generating ridiculously small keys, we can get stuck
* continually regenerating the same prime values. Check for
* this and bail if it happens 3 times. */
unsigned int degenerate = 0;
do {
if (!BN_generate_prime_ex(rsa->q, bitsq, 0, NULL, NULL, cb)) {
goto err;
}
} while ((BN_cmp(rsa->p, rsa->q) == 0) && (++degenerate < 3));
if (degenerate == 3) {
ok = 0; /* we set our own err */
OPENSSL_PUT_ERROR(RSA, keygen, RSA_R_KEY_SIZE_TOO_SMALL);
goto err;
}
if (!BN_sub(r2, rsa->q, BN_value_one()) ||
!BN_gcd(r1, r2, rsa->e, ctx)) {
goto err;
}
if (BN_is_one(r1)) {
break;
}
if (!BN_GENCB_call(cb, 2, n++)) {
goto err;
}
}
if (!BN_GENCB_call(cb, 3, 1)) {
goto err;
}
if (BN_cmp(rsa->p, rsa->q) < 0) {
tmp = rsa->p;
rsa->p = rsa->q;
rsa->q = tmp;
}
/* calculate n */
if (!BN_mul(rsa->n, rsa->p, rsa->q, ctx)) {
goto err;
}
/* calculate d */
if (!BN_sub(r1, rsa->p, BN_value_one())) {
goto err; /* p-1 */
}
if (!BN_sub(r2, rsa->q, BN_value_one())) {
goto err; /* q-1 */
}
if (!BN_mul(r0, r1, r2, ctx)) {
goto err; /* (p-1)(q-1) */
}
pr0 = &local_r0;
BN_with_flags(pr0, r0, BN_FLG_CONSTTIME);
if (!BN_mod_inverse(rsa->d, rsa->e, pr0, ctx)) {
goto err; /* d */
}
/* set up d for correct BN_FLG_CONSTTIME flag */
d = &local_d;
BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
/* calculate d mod (p-1) */
if (!BN_mod(rsa->dmp1, d, r1, ctx)) {
goto err;
}
/* calculate d mod (q-1) */
if (!BN_mod(rsa->dmq1, d, r2, ctx)) {
goto err;
}
/* calculate inverse of q mod p */
p = &local_p;
BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
if (!BN_mod_inverse(rsa->iqmp, rsa->q, p, ctx)) {
goto err;
}
ok = 1;
err:
if (ok == -1) {
OPENSSL_PUT_ERROR(RSA, keygen, ERR_LIB_BN);
ok = 0;
}
if (ctx != NULL) {
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
return ok;
}
const struct rsa_meth_st RSA_default_method = {
{
0 /* references */,
1 /* is_static */,
},
NULL /* app_data */,
NULL /* init */,
finish,
size,
NULL /* sign */,
NULL /* verify */,
encrypt,
sign_raw,
decrypt,
verify_raw,
private_transform,
mod_exp /* mod_exp */,
BN_mod_exp_mont /* bn_mod_exp */,
RSA_FLAG_CACHE_PUBLIC | RSA_FLAG_CACHE_PRIVATE,
keygen,
};